Long Term Evolution (LTE) using unlicensed carriers (LTE-U) means the deployment of LTE in unlicensed carriers to meet the growing capacity requirements of LTE systems and improve the using efficiency of the unlicensed spectrum. It may be an important direction of evolution for LTE and future wireless communications. In the design of LTE-U, it is necessary to consider how to compete for unlicensed carriers with Wireless Fidelity (WiFi), radar and other different systems and the same system of LTE-U in a fair and friendly manner for data transmission, and it is necessary to affect little to and retain LTE technical features as much as possible. The LTE-U system may also be referred to as a LTE Licensed Assisted Access (LAA) system.
In a scenario where there are a number of unlicensed carriers, for example, a 5G spectrum may use a maximum of 24 unlicensed carriers of 20M bandwidth. The LAA access point may scan and monitor multiple unlicensed carriers before using an unlicensed carrier to give priority selection to an unlicensed carrier with the relatively light or the cleanest load for the LAA's own use.
At present, for the carrier selection on the unlicensed spectrum (also known as channel selection), the LAA access point does not have other means except for energy detection and carrier sensing. The LAA access point cannot recognize other LAA access points. Therefore, the traditional art cannot provide the presence of neighboring access points, including the presence of neighboring LAA access points and WiFi access points. Neither can the traditional art indicate whether the LAA access point is applicable to the User Equipment (UE). Therefore, there is a need for a more comprehensive channel selection algorithm to solve the above technical problems.